collections

问题 So I am searching a huge ArrayList for a particular String value, but I need Collections.binarySearch() to return a value >=0 if the String I am looking for is equal( non case-sensitive) to the String I pass into the binarySearch() method. Now in the source code for Collections.binarySearch(), it eventually calls the following lines of code. Comparable<? super T> midVal = list.get(mid); int cmp = midVal.compareTo(key); So seen as I cannot override String as its final (therefore preventing me

问题 I'm trying to dynamically create a collection with collections nested within. So far, I've been able to create a nested collection by typing everything (see below). However, I have a ( horrible ) spreadsheet that has a repeating set of 17 questions hundreds of times in one column, and the answers in the next column. I'm trying to get the answer to each question as an item, and the question itself as the index. The unique set of the 17 questions will be a collection within a collection of the

问题 I am grouping and partioning a stream as follows: // Partioning Map<Boolean, List<Person>> partitioned = persons.stream(). collect(Collectors.partitioningBy(p -> p.getAge() > 20)); // Grouping Map<String, List<Person>> grouped = persons.stream() .collect(Collectors.groupingBy(p -> p.getCity())); Is there a way i can combine both of these? I tried combining both with using groupingBy inside partioningBy, but did not get the things right. Any suggestion? The expected result is the partition the

问题 i was just handed the following stack trace: 2015-12-20 07:43:36.151 -0800 ERROR o.s.s.s.TaskUtils$LoggingErrorHandler [taskExecutor-6] Unexpected error occurred in scheduled task. java.lang.StackOverflowError at java.util.Collections$UnmodifiableMap.get(Collections.java:1454) ~[?:1.8.0_65] at java.util.Collections$UnmodifiableMap.get(Collections.java:1454) ~[?:1.8.0_65] at java.util.Collections$UnmodifiableMap.get(Collections.java:1454) ~[?:1.8.0_65] at java.util.Collections$UnmodifiableMap

问题 To get a sequence with one value updated, one can use seq.updated(index, value) I want to set a new value for a range of elements. Is there a library function for that? I currently use the following function: def updatedSlice[A](seq: List[A], ind: Iterable[Int], value: A): List[A] = if (ind.isEmpty) seq else updatedSlice(seq.updated(ind.head, value), ind.tail, value) Besides the need of writing function, this seems to be inefficient, and also works only for lists, rather than arbitrary

问题 Newbie question. I have an original bean coming from the DB row-by-row as public class DataBean { private Integer employeeId; private String org; private String comments; // + Constructors, getters/setters } I need to map it to a different bean with multiple Org's grouped by Employee ID into a List. Only Orgs can be multiple for an EmployeeID; the Comments field is guaranteed to be the same. public class CustomDataBean { private Integer employeeId; private List<String> orgs; private String

问题 Some of the elements in the collections module seem to be uppercase, some other not. Is there a specific rationale behind it? 回答1: According to this reddit comment All classes written in python are upper camel case. All types based on C code are lower. [like the primitives] namedtuple is a function, thus follows the naming convention of functions. deque and defaultdict are types, (C); Counter and OrderedDict are classes, (Python). 来源： https://stackoverflow.com/questions/33636940/why-is

问题 Some of the elements in the collections module seem to be uppercase, some other not. Is there a specific rationale behind it? 回答1: According to this reddit comment All classes written in python are upper camel case. All types based on C code are lower. [like the primitives] namedtuple is a function, thus follows the naming convention of functions. deque and defaultdict are types, (C); Counter and OrderedDict are classes, (Python). 来源： https://stackoverflow.com/questions/33636940/why-is

问题 I would like to have some observable collections/sequences in Python that allow me to listen on change events, like for adding new items or updating items: list = ObservableList(['a','b','c']) list.addChangeListener(lambda new_value: print(new_value)) list.append('a') # => should trigger the attached change listener data_frame = ObservableDataFrame({'x': [1,2,3], 'y':[10,20,30]}) data_frame.addChangeListener(update_dependent_table_cells) # => allows to only update dependent cells instead of a

问题 I would like to have some observable collections/sequences in Python that allow me to listen on change events, like for adding new items or updating items: list = ObservableList(['a','b','c']) list.addChangeListener(lambda new_value: print(new_value)) list.append('a') # => should trigger the attached change listener data_frame = ObservableDataFrame({'x': [1,2,3], 'y':[10,20,30]}) data_frame.addChangeListener(update_dependent_table_cells) # => allows to only update dependent cells instead of a